Traditional placement of pipe underground relies on first drilling, boring, impact piercing, or trenching. In typical ground loop installations for geothermal systems, the pipe is then inserted in the bore or trench which is then back filled to eliminate voids. As an example, FIG. 1 depicts a cross sectional view of a typical ground loop installation. Here, hole 100 is drilled in ground material 110 (line 112 differentiating between above and below ground) to a desired depth. A loop or piping 120 having a u-shape is then placed into the hole. Only a portion of this piping being shown for ease of understanding. Of course, given the shape of the hole 100 and the piping 120, there can be significant gaps between the hole and the pipe. These gaps are then filled with grout (depicted as shaded area 130) which dries and solidifies in the hole around the piping. Because of the nature of grout, the likelihood of air pockets 140, 142 in the grout and around the piping is relatively high. These air pockets can reduce heat transfer between fluid, such as water, coolant, etc., in the pipes and the ground material thereby reducing the efficiency of the ground loop and the entire geothermal system.
Another traditional method of installing pipe underground involves pulling the pipe behind a pneumatic boring tool while creating an opening for the pipe. This process is useful for horizontal drilling, such as to place piping under a roadway, as the drill can be removed the far end of the pipe so that it can be recovered and the piping terminated. This technique is less useful for vertical drilling as the boring tool, which is fused to the pipe in order to pull it through the opening created by the boring tool, cannot be recovered by pulling it back through the pipe.